Scratch : Proyek Pertumbuhan N Hari & Proyek Capaian Pertumbuhan | Informatika Kelas 9

Summary

This video tutorial demonstrates how to create a bacterial growth forecasting application using Scratch. It explains the process of calculating bacterial growth by inputting initial values for day 1 and day 2 and forecasting future growth. The tutorial guides viewers through setting up variables, creating functions, and applying iterative processes to calculate the growth on any selected day. The video also includes modifying the program to forecast the number of days required for bacteria to reach a specific target. The step-by-step guide helps users learn Scratch programming by breaking down tasks into manageable parts.

Takeaways

• 😀 The project aims to create an application for bacterial growth prediction based on initial conditions and user-defined observation time.
• 😀 The script outlines a method to calculate bacterial growth by determining the ratio between consecutive days' growth and applying this ratio to predict future growth.
• 😀 It demonstrates how to implement the calculation of growth over n days by creating formulas and applying them in a simple coding platform like Scratch.
• 😀 The user is prompted to input the number of bacteria on day 1 and day 2, as well as the desired observation period, to forecast future growth.
• 😀 The formula for calculating the growth ratio is explained: it is the difference between day 2 and day 1, divided by day 1's bacteria count.
• 😀 After calculating the ratio, the application uses it to forecast the number of bacteria for subsequent days using a recurrence relation.
• 😀 Variables such as H1, H2, and HN are used to store initial values and the results of the calculations. The program uses broadcasts and functions for efficient processing.
• 😀 The application dynamically updates the growth predictions as the user inputs data and initiates the calculation with a click event.
• 😀 The script covers both predicting bacterial growth over a set number of days and determining how long it takes for a population to reach a target size.
• 😀 The application design ensures flexibility, allowing the user to adjust inputs and instantly see updated predictions, demonstrating the power of arithmetic progression and recurrence relations.

Q & A

What is the main focus of the video script?

The main focus of the video script is about developing an application for calculating bacterial growth over a specified period based on initial inputs of bacterial population growth over the first two days. The application is built using the Scratch platform.

How does the application determine bacterial growth?

The application calculates bacterial growth using a growth ratio derived from the difference between the second and first day's bacterial population, divided by the first day's population. The formula is then applied to calculate the population for any subsequent days.

What is the formula used to calculate the growth ratio?

The formula to calculate the growth ratio is: (H2 - H1) / H1, where H2 is the bacterial population on day 2 and H1 is the population on day 1.

What is the significance of the variable 'HN' in the program?

'HN' represents the bacterial population on the nth day. It is calculated using the formula HN = HN-1 + (ratio * HN-1), where HN-1 is the bacterial population on the previous day.

Why does the script use variables like 'H1', 'H2', and 'HN'?

These variables are used to store the bacterial population on different days. 'H1' stores the population on day 1, 'H2' on day 2, and 'HN' represents the population on any nth day, allowing for flexible calculations.

What is the purpose of the 'broadcast' function in the script?

The 'broadcast' function is used to trigger specific actions or events in the Scratch program, such as prompting the user for input or starting calculations. It helps coordinate the flow of actions within the application.

How does the program handle user input for the bacterial growth?

The program uses input fields to collect the initial bacterial populations for day 1 (H1) and day 2 (H2), as well as the number of days for which the user wants to forecast the bacterial growth. These inputs are stored in variables for use in calculations.

What modification does the script make in the second part of the application?

In the second part of the application, the user is asked to input a target number of bacteria. The program then calculates how many days it would take for the bacteria to reach or exceed the target number, using a repeat-until loop to stop when the population exceeds the target.

What does the script do if the user inputs a target number of bacteria?

If the user inputs a target number of bacteria, the script uses a 'repeat-until' loop to calculate how many days it would take for the bacterial population to exceed the target value. The loop continues until the bacterial population is greater than or equal to the target.

How does the application ensure accurate display of results?

The application uses a display list to show the bacterial population for each day. It ensures accurate display by clearing the list at the start and adding the calculated values for each day, based on the user's input and the program's calculations.